Extreme pressure lubricant



atented July 14, 1942 NHTEZ EXTREME PRESSURE LUBRICANT No D; awing. Application April 21, 1939, Serial No. 269,211

6 Slaims.

In some constructions and usages of gears and hearings or bearing surfaces, under working conditions there are such enormous unit pressures that customary lubricating oils cannot maintain a lubricating film. A number of so-called extreme pressure lubricants have been brought forth in an effort to meet such conditions. These are of the lead soap type or sulphur type or chlorine compound type, or less usually involve phosphates, phosphites, arsenites, etc. These compounds while being able to maintain a lubricating film, tend to affect the oil itself detrimentally, such as decreasing its resistance to oxidation and thickening, and such compounds also tend to decompose and proceed to rapid corrosion and damage to bearing surfaces; and like 001- loidal graphite are not very satisfactory where temperature raise and exposure to oxidizing conditions may be incurred. In accordance with the present invention, colloidal materials of peculiar character are employed to the production of extreme pressure lubricants having freedom from the detrimental tendencies of materials of organic character as noted, and lubricants in accordance with the present invention make possible excellent film maintenance in heavy load conditions.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described, and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative however, of but a few of the various ways in which the principle of the invention may be employed.

In accordance with the invention, dispersions in oil are prepared with colloids which have substantially a spherical shape as dispersed particles, in contrast to those whose particles are fiat such as the well-known colloidal graphite. These spherical colloid preparations give a remarkable lubricity, and the behavior is as though the lubricating film provided minute ball or roller bearings between the moving surfaces, instead of the sliding or slipping action had with the flat type of colloid particles such as colloidal graphite. These spherical-type colloidal materials may be made from various sources, inorganic or organic, and inorganic materials such as available metal oxides, sulphides and other spherical-colloidal particle providing compounds may be applied. Iron compounds for instance are easily prepared. As an example: Iron carbonyl is decomposed, as for instance by being admixed with air and a temperature of about 1000 F., the products Cornell machine fails at 1000 pounds load and projected into a reaction chamber where there is shows a torque failure at 20 pounds, and shows 0.05 asphaltenes, such oil colloidally ground with the F6203 as provided foregoing, and in the amount of 0.5 per cent, shows a load failure test 01 5000 pounds, torque failure at 48 pounds, and no asphaltenes.

The colloid material may be incorporated with the oil in amounts as desired, but usually 0.5-2 per cent is suflicient. Iron oxide prepared as above-noted is of particular fineness and lends itself well to colloidal grinding or dispersion. Iron carbonyl may also be decomposed otherwise, as by burning, hydrolysis or by vapor phase preparation in a light solvent. And, iron sulphide may also be suitably formed and be dispersed with oil, and as indicated, generally analogous spherical colloid particle providing materials may be employed. Such materials being characterized by great stability in themselves and having such fineness as to be capable of dispersing in the oil, and when so dispersed in oils of for instance -160 sec. Saybolt at 210 F., the material remains homogeneous without separaton. In some instances it is of advantage to employ a mixture, as for instance iron oxide and iron sulphide colloidally dispersed as shown.

Where employing spherical colloid particle material which is of metallic source, if the lubricant is to be used under particularly drastic conditions of elevated temperature and air exposure, I prefer a composition involving the oil base with the spherical colloidal particle material, and an agent which here acts as a metal inhibitor, by which I mean a phosphate or phosphite ester or condensation product of an aromatic aldehyde or its derivative with a diamine. The colloidal material may be mixed in the amounts as aboveindicated and the ester or condensation component may be in lesser amount, as for instance 0.0005 per cent.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

I therefore particularly point out and distinctly claim as my invention:

1. A lubricating composition comprising a lubricating oil having colloidally dispersed therein an iron compound from the group consisting of oxides and sulfides, said iron compound being present in relatively small but sufiicient amount to improve the extreme pressure properties of said oil.

2. A lubricating composition comprising a lubricating oil having colloidally dispersed therein iron oxide produced from decomposition of iron carbonyl, said iron oxide being present in relatively small but suficient amount of approximately 0.5% to 2% to improve the extreme pressure properties of said oil.

53. A lubricating composition comprising a lubricating oil having colloidaliy dispersed therein iron sulfide, said iron sulfide being present in relatively small but suflicient amount of approximately 0.5% to 2% to improve the extreme pressure properties of said oil.

4. The lubricating composition defined in claim 1 containing a. small amount of phosphate ester as an inhibitor.

5. The lubricating composition defined in claim 1 containing a small amount of phosphite ester as an inhibitor.

6. The lubricating composition defined in claim 1 containing as an inhibitor a small amount of condensation product of an aromatic aldehyde with a diamine.

ROBERT E. BURK. 

